/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    RemovePercentage.java
 *    Copyright (C) 2002 Richard Kirkby
 *
 */


package pATT.filters.unsupervised.instance;


import java.util.Enumeration;
import java.util.Vector;

import pATT.core.Instances;
import pATT.core.Option;
import pATT.core.OptionHandler;
import pATT.core.Utils;
import pATT.filters.Filter;
import pATT.filters.UnsupervisedFilter;

/**
 * This filter removes a given percentage of a dataset.
 *
 * Valid options are: <p>
 *
 * -V <br>
 * Specifies if inverse of selection is to be output.<p>
 *
 * -P percentage <br>
 * The percentage of instances to select. (default 50)<p>
 *
 * @author Richard Kirkby (eibe@cs.waikato.ac.nz)
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision: 1.3 $ 
 */
@SuppressWarnings("serial")
public class RemovePercentage extends Filter
implements UnsupervisedFilter, OptionHandler {
	
	/** Percentage of instances to select. */
	private int m_Percentage = 50;
	
	/** Indicates if inverse of selection is to be output. */
	private boolean m_Inverse = false;
	
	/**
	 * Gets an enumeration describing the available options..
	 *
	 * @return an enumeration of all the available options.
	 */
	@SuppressWarnings("unchecked")
	public Enumeration listOptions() {
		
		Vector newVector = new Vector(2);
		
		newVector.addElement(new Option(
				"\tSpecifies percentage of instances to select. (default 50)\n",
				"P", 1, "-P <percentage>"));
		
		newVector.addElement(new Option(
				"\tSpecifies if inverse of selection is to be output.\n",
				"V", 0, "-V"));
		
		return newVector.elements();
	}
	
	/**
	 * Parses the options for this object. Valid options are: <p>
	 *
	 * -P percentage <br>
	 * The percentage of instances to select. (default 50)<p>
	 *
	 * -V <br>
	 * Specifies if inverse of selection is to be output.<p>
	 *
	 * @param options the list of options as an array of strings
	 * @exception Exception if an option is not supported
	 */
	public void setOptions(String[] options) throws Exception {
		
		String percent = Utils.getOption('P', options);
		if (percent.length() != 0) {
			setPercentage(Integer.parseInt(percent));
		} else {
			setPercentage(50);
		}
		setInvertSelection(Utils.getFlag('V', options));
		
		if (getInputFormat() != null) {
			setInputFormat(getInputFormat());
		}
	}
	
	/**
	 * Gets the current settings of the filter.
	 *
	 * @return an array of strings suitable for passing to setOptions
	 */
	public String [] getOptions() {
		
		String [] options = new String [5];
		int current = 0;
		
		options[current++] = "-P"; options[current++] = "" + getPercentage();
		if (getInvertSelection()) {
			options[current++] = "-V";
		}
		
		while (current < options.length) {
			options[current++] = "";
		}
		return options;
	}
	
	/**
	 * Returns a string describing this filter
	 *
	 * @return a description of the filter suitable for
	 * displaying in the explorer/experimenter gui
	 */
	public String globalInfo() {
		
		return "A filter that removes a given percentage of a dataset.";
	}
	
	/**
	 * Returns the tip text for this property
	 *
	 * @return tip text for this property suitable for
	 * displaying in the explorer/experimenter gui
	 */
	public String percentageTipText() {
		
		return "The percentage of the data to select.";
	}
	
	/**
	 * Gets the percentage of instances to select.
	 * 
	 * @return the percentage.
	 */
	public int getPercentage() {
		
		return m_Percentage;
	}
	
	/**
	 * Sets the percentage of intances to select.
	 *
	 * @param percent the percentage
	 * @exception IllegalArgumentException if percenatge out of range
	 */
	public void setPercentage(int percent) {
		
		if (percent < 0 || percent > 100) {
			throw new IllegalArgumentException("Percentage must be between 0 and 100.");
		}
		m_Percentage = percent;
	}
	
	/**
	 * Returns the tip text for this property
	 *
	 * @return tip text for this property suitable for
	 * displaying in the explorer/experimenter gui
	 */
	public String invertSelectionTipText() {
		
		return "Whether to invert the selection.";
	}
	
	/**
	 * Gets if selection is to be inverted.
	 *
	 * @return true if the selection is to be inverted
	 */
	public boolean getInvertSelection() {
		
		return m_Inverse;
	}
	
	/**
	 * Sets if selection is to be inverted.
	 *
	 * @param inverse true if inversion is to be performed
	 */
	public void setInvertSelection(boolean inverse) {
		
		m_Inverse = inverse;
	}
	
	/**
	 * Sets the format of the input instances.
	 *
	 * @param instanceInfo an Instances object containing the input instance
	 * structure (any instances contained in the object are ignored - only the
	 * structure is required).
	 * @return true because outputFormat can be collected immediately
	 * @exception Exception if the input format can't be set successfully
	 */  
	public boolean setInputFormat(Instances instanceInfo) throws Exception {
		
		super.setInputFormat(instanceInfo);
		setOutputFormat(instanceInfo);
		return true;
	}
	
	/**
	 * Signify that this batch of input to the filter is
	 * finished. Output() may now be called to retrieve the filtered
	 * instances.
	 *
	 * @return true if there are instances pending output
	 * @exception IllegalStateException if no input structure has been defined 
	 */
	public boolean batchFinished() {
		
		if (getInputFormat() == null) {
			throw new IllegalStateException("No input instance format defined");
		}
		
		// Push instances for output into output queue
		Instances toFilter = getInputFormat();
		int cutOff = toFilter.numInstances() * m_Percentage / 100;
		
		if (m_Inverse) {
			for (int i = 0; i < cutOff; i++) {
				push(toFilter.instance(i));
			}
		} else {
			for (int i = cutOff; i < toFilter.numInstances(); i++) {
				push(toFilter.instance(i));
			}
		}
		m_NewBatch = true;
		return (numPendingOutput() != 0);
	}
	
	/**
	 * Main method for testing this class.
	 *
	 * @param argv should contain arguments to the filter: use -h for help
	 */
	public static void main(String [] argv) {
		
		try {
			if (Utils.getFlag('b', argv)) {
				Filter.batchFilterFile(new RemovePercentage(), argv);
			} else {
				Filter.filterFile(new RemovePercentage(), argv);
			}
		} catch (Exception ex) {
			System.out.println(ex.getMessage());
		}
	}
	
	@Override
	public boolean isSupervisedFilter() {
		return false;
	}
	
	@Override
	public boolean isAttributeFilter() {
		return false;
	}
	
	@Override
	public String moreInfo() {
		return globalInfo();
	}
	
	@Override
	public boolean hasDataInput() {
		
		return true;
	}
	
	@Override
	public String more() {
		return super.more(listOptions());
	}
	
	@Override
	public String getOption(String label) {
		if(label.equals("P"))
			return "percentage";
		else if(label.equals("V"))
			return "invertSelection";
		
		return "";
		
	}
	
	@Override
	public void cleanFields() {
		m_Percentage = 50;
		m_Inverse = false;	
	}
}



